forked from zhurui/management
290 lines
11 KiB
Markdown
290 lines
11 KiB
Markdown
|
[![npm][npm]][npm-url]
|
||
|
[![node][node]][node-url]
|
||
|
[![npm-stats][npm-stats]][npm-url]
|
||
|
[![deps][deps]][deps-url]
|
||
|
[![travis][travis]][travis-url]
|
||
|
[![appveyor][appveyor]][appveyor-url]
|
||
|
[![coverage][cover]][cover-url]
|
||
|
[![chat][chat]][chat-url]
|
||
|
|
||
|
<div align="center">
|
||
|
<img height="100"
|
||
|
src="https://worldvectorlogo.com/logos/sass-1.svg">
|
||
|
<a href="https://github.com/webpack/webpack">
|
||
|
<img width="200" height="200"
|
||
|
src="https://webpack.js.org/assets/icon-square-big.svg">
|
||
|
</a>
|
||
|
<h1>Sass Loader</h1>
|
||
|
<p>Loads a Sass/SCSS file and compiles it to CSS.</p>
|
||
|
</div>
|
||
|
|
||
|
Use the [css-loader](https://github.com/webpack-contrib/css-loader) or the [raw-loader](https://github.com/webpack-contrib/raw-loader) to turn it into a JS module and the [MiniCssExtractPlugin](https://github.com/webpack-contrib/mini-css-extract-plugin) to extract it into a separate file.
|
||
|
Looking for the webpack 1 loader? Check out the [archive/webpack-1 branch](https://github.com/webpack-contrib/sass-loader/tree/archive/webpack-1).
|
||
|
|
||
|
<h2 align="center">Install</h2>
|
||
|
|
||
|
```bash
|
||
|
npm install sass-loader node-sass webpack --save-dev
|
||
|
```
|
||
|
|
||
|
The sass-loader requires [webpack](https://github.com/webpack) as a
|
||
|
[`peerDependency`](https://docs.npmjs.com/files/package.json#peerdependencies)
|
||
|
and it requires you to install either [Node Sass][] or [Dart Sass][] on your
|
||
|
own. This allows you to control the versions of all your dependencies, and to
|
||
|
choose which Sass implementation to use.
|
||
|
|
||
|
[Node Sass]: https://github.com/sass/node-sass
|
||
|
[Dart Sass]: http://sass-lang.com/dart-sass
|
||
|
|
||
|
<h2 align="center">Examples</h2>
|
||
|
|
||
|
Chain the sass-loader with the [css-loader](https://github.com/webpack-contrib/css-loader) and the [style-loader](https://github.com/webpack-contrib/style-loader) to immediately apply all styles to the DOM.
|
||
|
|
||
|
```bash
|
||
|
npm install style-loader css-loader --save-dev
|
||
|
```
|
||
|
|
||
|
```js
|
||
|
// webpack.config.js
|
||
|
module.exports = {
|
||
|
...
|
||
|
module: {
|
||
|
rules: [{
|
||
|
test: /\.scss$/,
|
||
|
use: [
|
||
|
"style-loader", // creates style nodes from JS strings
|
||
|
"css-loader", // translates CSS into CommonJS
|
||
|
"sass-loader" // compiles Sass to CSS, using Node Sass by default
|
||
|
]
|
||
|
}]
|
||
|
}
|
||
|
};
|
||
|
```
|
||
|
|
||
|
You can also pass options directly to [Node Sass][] or [Dart Sass][]:
|
||
|
|
||
|
```js
|
||
|
// webpack.config.js
|
||
|
module.exports = {
|
||
|
...
|
||
|
module: {
|
||
|
rules: [{
|
||
|
test: /\.scss$/,
|
||
|
use: [{
|
||
|
loader: "style-loader"
|
||
|
}, {
|
||
|
loader: "css-loader"
|
||
|
}, {
|
||
|
loader: "sass-loader",
|
||
|
options: {
|
||
|
includePaths: ["absolute/path/a", "absolute/path/b"]
|
||
|
}
|
||
|
}]
|
||
|
}]
|
||
|
}
|
||
|
};
|
||
|
```
|
||
|
|
||
|
See [the Node Sass documentation](https://github.com/sass/node-sass/blob/master/README.md#options) for all available Sass options.
|
||
|
|
||
|
The special `implementation` option determines which implementation of Sass to
|
||
|
use. It takes either a [Node Sass][] or a [Dart Sass][] module. For example, to
|
||
|
use Dart Sass, you'd pass:
|
||
|
|
||
|
```js
|
||
|
// ...
|
||
|
{
|
||
|
loader: "sass-loader",
|
||
|
options: {
|
||
|
implementation: require("sass")
|
||
|
}
|
||
|
}
|
||
|
// ...
|
||
|
```
|
||
|
|
||
|
Note that when using Dart Sass, **synchronous compilation is twice as fast as
|
||
|
asynchronous compilation** by default, due to the overhead of asynchronous
|
||
|
callbacks. To avoid this overhead, you can use the
|
||
|
[`fibers`](https://www.npmjs.com/package/fibers) package to call asynchronous
|
||
|
importers from the synchronous code path. To enable this, pass the `Fiber` class
|
||
|
to the `fiber` option:
|
||
|
|
||
|
```js
|
||
|
// webpack.config.js
|
||
|
const Fiber = require('fibers');
|
||
|
|
||
|
module.exports = {
|
||
|
...
|
||
|
module: {
|
||
|
rules: [{
|
||
|
test: /\.scss$/,
|
||
|
use: [{
|
||
|
loader: "style-loader"
|
||
|
}, {
|
||
|
loader: "css-loader"
|
||
|
}, {
|
||
|
loader: "sass-loader",
|
||
|
options: {
|
||
|
implementation: require("sass"),
|
||
|
fiber: Fiber
|
||
|
}
|
||
|
}]
|
||
|
}]
|
||
|
}
|
||
|
};
|
||
|
```
|
||
|
|
||
|
### In production
|
||
|
|
||
|
Usually, it's recommended to extract the style sheets into a dedicated file in production using the [MiniCssExtractPlugin](https://github.com/webpack-contrib/mini-css-extract-plugin). This way your styles are not dependent on JavaScript:
|
||
|
|
||
|
```js
|
||
|
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
|
||
|
|
||
|
module.exports = {
|
||
|
...
|
||
|
module: {
|
||
|
rules: [{
|
||
|
test: /\.scss$/,
|
||
|
use: [
|
||
|
// fallback to style-loader in development
|
||
|
process.env.NODE_ENV !== 'production' ? 'style-loader' : MiniCssExtractPlugin.loader,
|
||
|
"css-loader",
|
||
|
"sass-loader"
|
||
|
]
|
||
|
}]
|
||
|
},
|
||
|
plugins: [
|
||
|
new MiniCssExtractPlugin({
|
||
|
// Options similar to the same options in webpackOptions.output
|
||
|
// both options are optional
|
||
|
filename: "[name].css",
|
||
|
chunkFilename: "[id].css"
|
||
|
})
|
||
|
]
|
||
|
};
|
||
|
```
|
||
|
|
||
|
<h2 align="center">Usage</h2>
|
||
|
|
||
|
### Imports
|
||
|
|
||
|
webpack provides an [advanced mechanism to resolve files](https://webpack.js.org/concepts/module-resolution/). The sass-loader uses Sass's custom importer feature to pass all queries to the webpack resolving engine. Thus you can import your Sass modules from `node_modules`. Just prepend them with a `~` to tell webpack that this is not a relative import:
|
||
|
|
||
|
```css
|
||
|
@import "~bootstrap/dist/css/bootstrap";
|
||
|
```
|
||
|
|
||
|
It's important to only prepend it with `~`, because `~/` resolves to the home directory. webpack needs to distinguish between `bootstrap` and `~bootstrap` because CSS and Sass files have no special syntax for importing relative files. Writing `@import "file"` is the same as `@import "./file";`
|
||
|
|
||
|
### Problems with `url(...)`
|
||
|
|
||
|
Since Sass/[libsass](https://github.com/sass/libsass) does not provide [url rewriting](https://github.com/sass/libsass/issues/532), all linked assets must be relative to the output.
|
||
|
|
||
|
- If you're just generating CSS without passing it to the css-loader, it must be relative to your web root.
|
||
|
- If you pass the generated CSS on to the css-loader, all urls must be relative to the entry-file (e.g. `main.scss`).
|
||
|
|
||
|
More likely you will be disrupted by this second issue. It is natural to expect relative references to be resolved against the `.scss` file in which they are specified (like in regular `.css` files). Thankfully there are a two solutions to this problem:
|
||
|
|
||
|
- Add the missing url rewriting using the [resolve-url-loader](https://github.com/bholloway/resolve-url-loader). Place it before the sass-loader in the loader chain.
|
||
|
- Library authors usually provide a variable to modify the asset path. [bootstrap-sass](https://github.com/twbs/bootstrap-sass) for example has an `$icon-font-path`. Check out [this working bootstrap example](https://github.com/webpack-contrib/sass-loader/tree/master/test/bootstrapSass).
|
||
|
|
||
|
### Extracting style sheets
|
||
|
|
||
|
Bundling CSS with webpack has some nice advantages like referencing images and fonts with hashed urls or [hot module replacement](https://webpack.js.org/concepts/hot-module-replacement/) in development. In production, on the other hand, it's not a good idea to apply your style sheets depending on JS execution. Rendering may be delayed or even a [FOUC](https://en.wikipedia.org/wiki/Flash_of_unstyled_content) might be visible. Thus it's often still better to have them as separate files in your final production build.
|
||
|
|
||
|
There are two possibilities to extract a style sheet from the bundle:
|
||
|
|
||
|
- [extract-loader](https://github.com/peerigon/extract-loader) (simpler, but specialized on the css-loader's output)
|
||
|
- [extract-text-webpack-plugin](https://github.com/webpack-contrib/extract-text-webpack-plugin) (more complex, but works in all use-cases)
|
||
|
|
||
|
### Source maps
|
||
|
|
||
|
To enable CSS source maps, you'll need to pass the `sourceMap` option to the sass-loader *and* the css-loader. Your `webpack.config.js` should look like this:
|
||
|
|
||
|
```javascript
|
||
|
module.exports = {
|
||
|
...
|
||
|
devtool: "source-map", // any "source-map"-like devtool is possible
|
||
|
module: {
|
||
|
rules: [{
|
||
|
test: /\.scss$/,
|
||
|
use: [{
|
||
|
loader: "style-loader"
|
||
|
}, {
|
||
|
loader: "css-loader", options: {
|
||
|
sourceMap: true
|
||
|
}
|
||
|
}, {
|
||
|
loader: "sass-loader", options: {
|
||
|
sourceMap: true
|
||
|
}
|
||
|
}]
|
||
|
}]
|
||
|
}
|
||
|
};
|
||
|
```
|
||
|
|
||
|
If you want to edit the original Sass files inside Chrome, [there's a good blog post](https://medium.com/@toolmantim/getting-started-with-css-sourcemaps-and-in-browser-sass-editing-b4daab987fb0). Checkout [test/sourceMap](https://github.com/webpack-contrib/sass-loader/tree/master/test) for a running example.
|
||
|
|
||
|
### Environment variables
|
||
|
|
||
|
If you want to prepend Sass code before the actual entry file, you can set the `data` option. In this case, the sass-loader will not override the `data` option but just append the entry's content. This is especially useful when some of your Sass variables depend on the environment:
|
||
|
|
||
|
```javascript
|
||
|
{
|
||
|
loader: "sass-loader",
|
||
|
options: {
|
||
|
data: "$env: " + process.env.NODE_ENV + ";"
|
||
|
}
|
||
|
}
|
||
|
```
|
||
|
|
||
|
**Please note:** Since you're injecting code, this will break the source mappings in your entry file. Often there's a simpler solution than this, like multiple Sass entry files.
|
||
|
|
||
|
<h2 align="center">Maintainers</h2>
|
||
|
|
||
|
<table>
|
||
|
<tr>
|
||
|
<td align="center">
|
||
|
<a href="https://github.com/jhnns"><img width="150" height="150" src="https://avatars0.githubusercontent.com/u/781746?v=3"></a><br>
|
||
|
<a href="https://github.com/jhnns">Johannes Ewald</a>
|
||
|
</td>
|
||
|
<td align="center">
|
||
|
<a href="https://github.com/webpack-contrib"><img width="150" height="150" src="https://avatars1.githubusercontent.com/u/1243901?v=3&s=460"></a><br>
|
||
|
<a href="https://github.com/webpack-contrib">Jorik Tangelder</a>
|
||
|
</td>
|
||
|
<td align="center">
|
||
|
<a href="https://github.com/akiran"><img width="150" height="150" src="https://avatars1.githubusercontent.com/u/3403295?v=3"></a><br>
|
||
|
<a href="https://github.com/akiran">Kiran</a>
|
||
|
</td>
|
||
|
<tr>
|
||
|
</table>
|
||
|
|
||
|
|
||
|
<h2 align="center">License</h2>
|
||
|
|
||
|
[MIT](http://www.opensource.org/licenses/mit-license.php)
|
||
|
|
||
|
[npm]: https://img.shields.io/npm/v/sass-loader.svg
|
||
|
[npm-stats]: https://img.shields.io/npm/dm/sass-loader.svg
|
||
|
[npm-url]: https://npmjs.com/package/sass-loader
|
||
|
|
||
|
[node]: https://img.shields.io/node/v/sass-loader.svg
|
||
|
[node-url]: https://nodejs.org
|
||
|
|
||
|
[deps]: https://david-dm.org/webpack-contrib/sass-loader.svg
|
||
|
[deps-url]: https://david-dm.org/webpack-contrib/sass-loader
|
||
|
|
||
|
[travis]: http://img.shields.io/travis/webpack-contrib/sass-loader.svg
|
||
|
[travis-url]: https://travis-ci.org/webpack-contrib/sass-loader
|
||
|
|
||
|
[appveyor-url]: https://ci.appveyor.com/project/webpack-contrib/sass-loader/branch/master
|
||
|
[appveyor]: https://ci.appveyor.com/api/projects/status/rqpy1vaovh20ttxs/branch/master?svg=true
|
||
|
|
||
|
[cover]: https://codecov.io/gh/webpack-contrib/sass-loader/branch/master/graph/badge.svg
|
||
|
[cover-url]: https://codecov.io/gh/webpack-contrib/sass-loader
|
||
|
|
||
|
[chat]: https://badges.gitter.im/webpack/webpack.svg
|
||
|
[chat-url]: https://gitter.im/webpack/webpack
|